--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/OrthancStone/Sources/Platforms/WebAssembly/WebAssemblyCairoViewport.cpp	Sat Jan 29 12:47:32 2022 +0100
@@ -0,0 +1,119 @@
+/**
+ * Stone of Orthanc
+ * Copyright (C) 2012-2016 Sebastien Jodogne, Medical Physics
+ * Department, University Hospital of Liege, Belgium
+ * Copyright (C) 2017-2022 Osimis S.A., Belgium
+ * Copyright (C) 2021-2022 Sebastien Jodogne, ICTEAM UCLouvain, Belgium
+ *
+ * This program is free software: you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program. If not, see
+ * <http://www.gnu.org/licenses/>.
+ **/
+
+
+#if defined(ORTHANC_BUILDING_STONE_LIBRARY) && ORTHANC_BUILDING_STONE_LIBRARY == 1
+#  include "WebAssemblyCairoViewport.h"
+#  include "../../../OrthancStone/Sources/Scene2D/CairoCompositor.h"
+#  include "../../../OrthancStone/Sources/Scene2DViewport/ViewportController.h"
+#else
+// This is the case when using the WebAssembly side module, and this
+// source file must be compiled within the WebAssembly main module
+#  include <Viewport/WebAssemblyCairoViewport.h>
+#  include <Scene2D/CairoCompositor.h>
+#  include <Scene2DViewport/ViewportController.h>
+#endif
+
+
+#include <Images/Image.h>
+
+namespace OrthancStone
+{
+  void WebAssemblyCairoViewport::Paint(ICompositor& compositor,
+                                       ViewportController& controller)
+  {
+    compositor.Refresh(controller.GetScene());
+
+    // Create a temporary memory buffer for the canvas in JavaScript
+    Orthanc::ImageAccessor cairo;
+    dynamic_cast<CairoCompositor&>(compositor).GetCanvas().GetReadOnlyAccessor(cairo);
+
+    const unsigned int width = cairo.GetWidth();
+    const unsigned int height = cairo.GetHeight();
+
+    if (javascript_.get() == NULL ||
+        javascript_->GetWidth() != width ||
+        javascript_->GetHeight() != height)
+    {
+      javascript_.reset(new Orthanc::Image(Orthanc::PixelFormat_RGBA32, width, height,
+                                           true /* force minimal pitch */));
+    }
+      
+    // Convert from BGRA32 memory layout (only color mode supported
+    // by Cairo, which corresponds to CAIRO_FORMAT_ARGB32) to RGBA32
+    // (as expected by HTML5 canvas). This simply amounts to
+    // swapping the B and R channels. Alpha channel is also set to
+    // full opacity (255).
+    uint8_t* q = reinterpret_cast<uint8_t*>(javascript_->GetBuffer());
+    for (unsigned int y = 0; y < height; y++)
+    {
+      const uint8_t* p = reinterpret_cast<const uint8_t*>(cairo.GetConstRow(y));
+      for (unsigned int x = 0; x < width; x++)
+      {
+        q[0] = p[2];  // R
+        q[1] = p[1];  // G
+        q[2] = p[0];  // B
+        q[3] = 255;   // A
+
+        p += 4;
+        q += 4;
+      }
+    }
+
+    if (width != 0 &&
+        height != 0)
+    {
+      // Execute JavaScript commands to blit the image buffer onto the
+      // 2D drawing context of the HTML5 canvas
+      EM_ASM({
+          const data = new Uint8ClampedArray(Module.HEAP8.buffer, $1, 4 * $2 * $3);
+          const img = new ImageData(data, $2, $3);
+          const ctx = document.getElementById(UTF8ToString($0)).getContext('2d');
+          ctx.putImageData(img, 0, 0);
+        },
+        GetCanvasId().c_str(),      // $0
+        javascript_->GetBuffer(),   // $1
+        javascript_->GetWidth(),    // $2
+        javascript_->GetHeight());  // $3
+    }
+  }
+    
+
+  WebAssemblyCairoViewport::WebAssemblyCairoViewport(const std::string& canvasId,
+                                                     bool enableEmscriptenMouseEvents) :
+    WebAssemblyViewport(canvasId,enableEmscriptenMouseEvents)
+  {
+    RefreshCanvasSize();
+    AcquireCompositor(new CairoCompositor(GetCanvasWidth(), GetCanvasHeight()));
+  }
+  
+
+  boost::shared_ptr<WebAssemblyCairoViewport> WebAssemblyCairoViewport::Create(
+    const std::string& canvasId, bool enableEmscriptenMouseEvents)
+  {
+    boost::shared_ptr<WebAssemblyCairoViewport> that = boost::shared_ptr<WebAssemblyCairoViewport>(
+        new WebAssemblyCairoViewport(canvasId, enableEmscriptenMouseEvents));
+    
+    that->WebAssemblyViewport::PostConstructor();
+    return that;
+  }
+}